Mechanical pencil



April 12,71932. G. A. COOPER MECHANICAL PENCIL Filedoct. 15, 1930 f fumfey 7e/m- [ba/per @y lII I II I Patented Apr. 12, 1932 UNITED STATES PA'rEN'r;1 OFFICE GLENN A. COOPER, OF CHICAGO, ILLINOIS, ASSIGNOR TO CRUVER MANUFACTURING COMPANY, OF CHIGAGO, ILLINOIS, .A CORPORATION OF ILLINOIS MECHANICAL :PENCIL Application led October 15, 1930. Serial No. 488,823.

This invention relates to improvements in mechanical pencils of the type wherein the lead is projected, ejected and retracted by relatively rotating the barrel and point portions of the pencil casing.

The main object of the present invention is to provide an improved means whereby an element of the projecting, ejecting and retracting mechanism is normally frictionally held against rotation but may be rotated after the reciprocable elements of said mechanism attain either limit of their movement thereby to avoid breakage or other damage to said mechanism by forcible relative rotation of said casing elements after said reciprocable elements have attained either limit of their movement.

The invention is fully illustrated in the accompanying drawings wherein:

Fig. 1 is a view in elevation, partly in section, of a pencil constructed in accordance with the invention.

Fig. 2 is a fragmentary central longitudinal section of the same showing certain parts of the mechanism in elevation.

Fig. 3 is a fragmentary central longitudinal section of the same showing all parts of the said mechanism, except'the ejector rod, in section.

Fig. 4 is a detail perspective view ofja sleeve rigid with the barrel of the casing. F'Fig. 5 is a plan section on the line 5-5 of The structure comprises the barrel'l of the casing having a cylindrical lower end portion of smaller diameter terminating in an annular shoulder 2 at one end and in a tapered extremity 3. Said barrel is preferably equipped with the usual clip 4 and cap 5. Said barrel 1 may be composed of any suitable material and, externally, may be of any desired cross-sectional shape.

The point portion or member 6 of the casing is preferably made of a suitable sheet metal. The upper end portion 7 of said member 6 is cylindrical and snugly fits the cylindrical lower end portion of the barrel 1, the rim of said ortion 7 engaging the shoulder 2. The bo y portion of said member 6 is tapered and presents an opening at its lower end which is axially aligned with the barrel 1 and is of substantially the same diameter as the lead 8.

Rigidly mounted in said tapered portion of the member 6, between the extremity and cylindrical portion 7 thereof, is a cup-like member 9 presenting a tapered upper end portion which is suitably secured to the member 6 by sweating or otherwise. This member 9 has a bottom wall 10 and is equipped with an axially disposed sleeve 11 projecting toward the extremity of the member 6.

A tube 12 is driven through said sleeve 11 so that its lower end portion projects to a point adjacent the extremity of the member 6, the lower end portion of which has a stepped cylindrical bore extending, as to the smaller diameter portion thereof, from the aforesaid opening to an annular shoulder 13 and, as to its larger diameter portion, from said shoulder 13 to the annular shoulder 14, the inner surface of the member 6 being tapered from a point 14a inwardly of said shoulder 14 to said cylindrical portion 7, thus providing a third cylindrical bore portion 14b which is of larger diameter than the bore prtion lying between the shoulders 13 and The said tube 12 is of substantially the exact diameter as the larger bore portion 14b above or inwardly of the said shoulder 14 and projects into said bore portion 14" with its lower end opposed to but not necessarily engaged with said shoulder 14.

The engagement of said tube 12 with the sleeve 11 is of the type known as a driveit which serves effectively to prevent either a rotary or longitudinal movement of said tube 12 relatively to the member 6.

The upper end portion of said tube 12 is provided with a continuous longitudinal slot 15 extending from the wall 10 of the member 9 to the upper end of said tube.

Mounted in the barrel is a tubular member 16, the lower endportion of which is of larger diameter than its upper end portion 17, said lower end portion being secured `within the lower end portion ofthe barrel 1 by drivefit or otherwise to prevent relative rotation and longitudinal movement between said barrel and said tube. The upperend portion 17 of said tubular member 16 is very shghtly eccentric to said lower end portlon thereof.

The tube 12 extends axially through thelower end portion of the tubular member 16 and is, consequently, slightly eccentric to the upper end portion 17 thereof.

A tube 18 equipped with a helical slot 19 extending from end to end thereof, snugly lits the upper end portion 17 of the tubular member 16. Said tube 18 extends from the wall 10 of the member 9 to a point adjacent the upper end of the tube 12 and is confined against longitudinal movement between said `wall 10 and a cross-pin 20 in the upper end of said tube 12.

Between the lower and upper end portions of the tubular member 16 is a tapered portion 21 of suiicient length to be suficiently yielding or elastic for the purposes of the structure as hereinafter more fully explained. The engagement of the tube 18 with the upper end portion 17 of the member 16 is such that free rotation of said tube 18 relatively to said portion 17 is firmly frictionally resisted while permitting such rotation and the withdrawal of said tube 18 with the point portion 6 of the casing upon removal ofthe latter.

Reciprocably mounted within the tube 12 (is a tube 22 having longitudinal slots 23 in its lower end portion to render the latter expansible, the bore of said tube 22 being slightly less than that of the lead 8 and is adapted to receive and yieldingly engage the upper or inner end portion of the latter. At its upper end, said tube is provided with a lateral projection 24 which engages in the slot 15 of the tube 12 and in the slot 19 of the tube 18 so that it is held against rotation relatively to the tube 12 and is caused to move longitudinally relatively to the latter to project and retract the lead 8 as said tube 12 is rotated relatively to the tube 18 in respectively opposite directions.

The ejector rod 25 has a straight lower end portion which lies withinthe tube 22, the upper end portion 26 thereof being bent to Vextend. slightly angularly to said lower end portion and present an elbow 27 which bears upon the inner wall of the tube 12, said elbow 27 being at the junction of the portion 26 of said rod 25 and the laterally projecting arm 28 thereof which extends through the slot 15 of the tube 12 and into but not through the slot 19 of the tube 18. The arm 28 of the rod 25 is spaced from the projection 24 of the tube 22, (said projection 24 being also of such length as to project into but not through said slot 19 of the .tube 18) a distance equal to the spacing of one convolution of the slot 19 from another.

The said tube 18 is cut away at its lower end to provide a shoulder 29 which is spaced from the lower terminal of said slot 19 sub stantially one hundred eighty degrees or more so that as said projection 24 of the tube 22 passes out of said slot 19 it will, upon further rotation of said tube 12 relatively to the tube 18, engage the said shoulder 29 and be confined against longitudinal movement, between said wall 10 and the lower end wall of the tube 18 between said shoulder 29 and the lower terminal of the slot 19. During this relative arcuate movement between the tube 22 and the tube 18, the arm 28 will con-` tinue downward travel and the rod 25 will thus be moved longitudinally relatively to the tube 22 a distance suiicient to eject the lead 8 out of engaging relation to said tube 22, the normal position of the lower extremity of said rod 25 with respect to the lower` end portion of the tube 22 being such that it constitutes a stop against which the upper end of the lead 8 ab-uts when engaged in said tube 22.

It will be obvious that after the projection 24 of the tube 22 has engaged the said shoulder 29, the ejector rod 25 will be disposed at the lower limit of its movement and that further forced relative rotation of the barrel 1 and member 6 in this direction will cause the tube 18 to rotate in unison with the tube 12 without causing any longitudinal movement of the rod 25 or tube 22.

Upon reversing this direction of rotation, the ejector rod will first be retracted to normal position whereupon a lead 8 may be engaged With the tube 22, and -continued rotation will cause the projection 24 to be engaged by the wall of the slot 19 arcuately opposed to the shoulder 29 and thus to re-enter said slot.

As the rod 25 attains the upper limit of its movement, it engages the cross-pin at the inner end of the tube 12 so that a further forced relative rotation of the barrel 1 and member 6 will cause the tubes 12 and 18 to again rotate in unison, thereby to so limit the strain or stress upon the operative elements of the mechanism as to prevent either breakage or distortion thereof.

The eccentricity of the portion 27 of the tubular member 26 as above pointed out, obviously serves to effect a very slight flexing of the tube 12 which is suiicient to impart slight frictional resistance against its rotation relatively to the tube 18 and tends also to slightly fiex the latter and the portion 17 of the member 16.

I claim as my invention:

1. A pencil structure' of the type specified comprising a casing -consisting of two relatively rotatable members, a sleeve for each member rigid therewith, the sleeve of one of said members including a smaller diameter end portion slightly eccentric to the body portion thereof, a longitudinally slotted tube rigid with one of said sleeves, a helically slotted tube rotatably engaged with the other of said tubes and engaged against longitudinal movement relatively to said slotted tube, and a lead engaging member and an ejector rod housed by said slotted tube and each equipped with a projection passing through 6l the slot thereof and engaging in the helical slot of the other tube.

2. A pencil structure of the type specified comprising a casing consisting of two relatively rotatable members, an axially aligned 10 sleeve rigid with one of said members, a sleeve comprisin a large diameter portion and a smaller diameter portion rigid with the other of said members, said smaller diameter portion of said last-named member being 16 slightly eccentric to the larger diameter portion thereof and connected therewith by a tapered intermediate portion, a longitudinally slotted tube rigid with the irst-mentioned sleeve, a helically slotted tube snugly fitting 20 and rotatable and slidable in the smaller diameter portion of the other of said sleeves and receiving said slotted tube, means confining said tubes against relative longitudinal movement, and a lead engaging and a lead ejecting member respectively housed by said longitudinally slotted tube and engaged with said helically slotted tube.

1n testimony whereof I have hereunto set my hand.

GLENN A. COOPER. 

